It has previously been proposed--see German Patent Disclosure Document DE-OS No. 16 63 153, RICK, assigned to the assignee of the present application--to so design a claw-pole alternator that vanes are provided located between the claws of the claw pole, extending longitudinally at an inclination with respect to the axis of rotation of the rotor, and projecting radially from the rotor axis. Claw-pole generators of this type usually have two axial ferromagnetic pole disks which are engaged, axially, against a tubular iron core on which the field coil is wound. The claw poles are customarily unitary with the pole disks and overlap the exciter or field coil, being interdigited and essentially trapezoidal in top view. In accordance with the disclosure of the referenced German document No. 16 63 153, ventilating vanes are located between the interdigited claw poles.
The ventilating vanes provide for increased axial air flow, the hence air cooling of the internal structure of the alternator. It has been found that, at high speeds of the alternator, the centrifugal forces to which the vanes are subjected can be so high that lateral attachment of the vanes along the longitudinal axis of the claw poles is not enough to reliably retain the vanes in position. The increasing top speeds of automotive engines, thus, require an improvement in the previously designed structure.